A conventional wireless tire pressure monitoring system includes a valve pressure sensor & transmitter for sensing tire pressure from each car wheel and remotely transmitting the tire-pressure signal; and a receiver for receiving the tire-pressure signal sent from the tire pressure sensor & transmitter for monitoring the tire pressure in each car wheel for enhancing car driving safety. 
If the receiver is powered by (at least) a dry cell which is independently separated from the original car power-supply (battery) system, the used cell should be always be replaced with new one, thereby causing inconvenience for the power supply of the wireless tire pressure monitoring system. 
If the receiver is electrically connected to the battery originally provided in the car, an electric wiring system should be additionally implemented in order to supply power source from the car battery to the tire pressure monitoring system, also causing inconvenience for those cars intended to be further equipped with such a wireless tire pressure monitoring system. 
The present inventor has found the drawbacks of the conventional wireless tire pressure monitoring system, and invented the present tire pressure alarming system by directly supplying  power to the alarming system from the car cigarette-lighter receptacle. 